Among the greatest things Jagex can do would be to RS gold eliminate most of the teleports from the sport, or create them quite a bit harder to use beyond basic hub teleportation. Adding so many teleports has made the entire world map look far, far smaller. Secondly, it would do nicely to significantly increase the size of nearly everything. The wild lands there may be, the further we would feel immersed in the dream world where we're the adventurers who journey from the peak of civilisation into the insides of badlands.
Inevitably, using a properly large draw space the small size of the map will be evident. A few important modifications jagex could make to alleviate that: Reshape mountain ranges. Currently, we've got a few influential mountains: those east of Varrock, these north of Burthorpe, those south of Al Kharid, and those west of Ardougne. Making them feel more realistic and creating rivers and so on flow well from them could be massive in making the map more plausible. Make the woods huge. Really, much bigger. This includes swamps etc.. Making them bigger the farther from civilisation we go would make those places feel considerably more wild.
Add more threat into the interior of those woods. The majority of the map reflects a universe which is logical for a mid to low level player, to whom dragon would be an unusual material to see and Barrows armour extremely infrequent. The most dangerous areas just aren't dangerous. Literally adding boss monsters to the centers of these forests would massively increase their danger. However, that's only possible if these areas are big enough which you can go about them if you know where you are. Make the in-game universe map less precise. If you could make it so that players needed to explore every area before it was completely documented in the map which would make a big difference to the adventuring feel. New lands would really be alien.
Have fewer artificial obstacles. That is a massive immersion breaker. If cliffs were scalable but required time and equipment, if borders weren't literally wooden fences we might jump , if rivers weren't literal walls but instead obstacles that would be drifted more than if you had the ideal equipment, that would be excellent.
There's creatures, but nothing to bind you to the fights, there's training areas, but no grounds to use them. You do not get lost in the fantasy of the landscaping since there's nothing to get lost in other than aesthetics, and you are just twiddling your thumbs waiting to get to another port of call, which, can go partially hand in hand with your suggestion of increasing the difficulty, but it will require more than that. Very good point. Jagex has done a couple of things to cheap RuneScape gold adress this, but it does not work for veteran gamers. The key ones are: Quests. I moved to Karamja to quest, like I moved to the desert and Morytania. That's the big reason to visit those areas, but the problem is that once you're done there, you're done.